Insecticidal organophosphorus esters of dihydrothienyl 1, 1-dioxide



United States Patent 3,234,084 INSECTICIDAL ORGANOPHGSPHORUS E5TERS 0F DIHYDROTHIENYL Lil-DIOXIDE Peter E. Newallis, Morris Plains, Ni, assignor to Monsanto Company, a corporation of Delaware N0 Drawing. Original application May 2, 1960, er. No. 25,823, new Patent No. 3,106,565, dated Get. 8, 1963. Divided and this application Nov. 1, 1962, Ser. No.

12 Claims. (Cl. 167-33) This application is division of copending application of Serial No. 25,823, filed May 2, 1960, now US. Patent wherein X is a chalkogen of atomic weight less than 40 (i.e. sulfur or oxygen) and wherein R and R are like or unlike alkyl radicals containing from 1 to 5 carbon atoms (e.g. methyl, ethyl, propyl, butyl, amyl, and the various isomeric forms thereof). It is preferred that R and R be alkyl radicals containing not more than 2 carbon atoms (e.g. methyl, ethyl).

The .phosphorothioates of this invention can be prepared by reacting in a fiuid medium (i.e. a temperature above the freezing point of the system up to and including the systems boiling point but preferably in the range of C. to 120 C.) a halide of the structure wherein D is a halogen having an atomic number above 9 but not higher than (i.e. chlorine or bromine) with a substantially equimolar amount of a salt (i.e. ammonium or alkali metal such as sodium, potassium or lithium) of a phosphorothioic acid of the structure wherein R, R and X have the aforedescribed significance in the presence of an inert organic liquid or solvent (e.g.

benzene, toluene, Xylene, acetone, butanone, clioxane,

carbon tetrachloride, etc.).

As illustrative of the phosphor-othioates of this invention are:

S-( 1,1-dioxo-2,B-dihydrothien-B-yl) 0,0-dimethyl phosphorothioate S- 1,1-dioxo-2,3-dihydrothien-3-yl) 0,0-dimethyl phosphorodithioate S-( 1,1-dioXo-2,3-dihydrothien-3-yl) 0,0-diethyl phosphorothioate S-( l,1-dioxo-2,3-dihydr0thien3-yl) 0,0-diethyl phosphorodithioate S-( 1,1-dioxo-2,3-dihydrothien-3-yl) 0,0-diisopropyl phosphorodithioate S-(1,1-dioXo-2,3-dihydrothien-3-yl) 0,0-diisobutyl phosphorodithioate 3,234,084 Patented Feb. 8, 1966 ice S 1, l-dioxo-Z,3-dihydrothien-3-yl) 0,0-dis0amyl phosphorothioate As illustrative of the preparation of the phosphorothioates of this invention is the following:

Example I To a suitable reaction vessel equipped with a thermometer, agitator and reflux condenser is charged approximately parts by weight of acetone and 15.4 parts by weight of. 3-bromo-1,1-dioXo-2,3-dihydro-thiophene and to this mix is added 14.6 parts by weight of ammonium 0,0-diethyl phosphorothioate dissolved in parts by weight of acetone. The mass is heated with agitation at reflux for 3 hours. The reaction mass is then filtered and the filtrate subjected to vacuum distillation to remove the acetone. The residue is then taken, up with methylene chloride and the organic solution washed first with 3% aqueous sodium carbonate and then with water. The sowashed organic solution is then subjected to vacuum distillation to remove the methylene dichloride and other volatiles. The residue, an amber liquid, isv S-(1,1-dioxo- 2,3 dihydrothien 3 yl) 0,0-diethyl phosphorothioate which is soluble in benzene and chloroform but insoluble in water.

Example II Example III Employing the procedure of Example I but replacing ammonium 0,0-diethyl phosphorothioate with an equimolar amount of ammonium 0,0-dimethyl phosphorodithioate there is obtained S (1,l-dioxo-2,3-d-ihydrothien-3-yl) 0,0-dimethylphosphorodithioate, an amber oil which is soluble in benzene but insoluble in Water.

Example IV Employing the procedure of Example I but replacing ammonium 0,0-diethyl phosphorothioate with an equimolar amount of ammonium 0,0-diisopropyl phosphorodithioate there is obtained S-(l,l-dioxo-2,3-dihydrothien-3-yl) 0,0-(llllSOPIOPYl 'phosphorodithioate, an amber oil which is soluble in benzene and chloroform but insoluble in water.

The methods by which the phosphorothioates of this invention are isolated will vary slightly with the reactants employed and the product produced. Further purification by selective solvent extraction or by absorptive agents such as activated carbon or clays can precede the removal of the inert organic liquid or solvent. Additionally an inert organic solvent can be added toand in the purification by absorptive agents. However, the product is generally satisfactory for insecticidal purposes without further purification.

It will be understood that the terms. insect and insecticide unless otherwise modified are used herein in their broad common usage to include spiders, mites, ticks, and like pests which are not in the strict biological sense classed as insects. Thus, the usage herein conforms to the definitions provided by Congress in Public 3 i Law 104, the Federal Insecticide, Fungicide, and Rodenticide Ac" of 1947, Section 2, subsectionh, wherein the term insect is used to refer not only to those small invertebrate animals belonging mostly-to the class In secta, comprising six-legged usually winged forms, as

beetles, bugs, bees, flies, and so forth, but also to other allied classes of arthropodsawhose members are wingless and usually have more than six legs, as spiders, mites,

ticks, centipedes, and wood'lice."

The phosphorothioates of this invention are effective againt a wide variety. of insect pests. the activity butnot limitative thereof is'the following:

One gram of S-(1,1-dioxo-2,3-dihydrothien-3-yl) 0,0- diethyl phosphorodithioate was dissolved in sufficient: acetone to make a concentrate solution; thereof. Approximately 0.1 cc. of sorbitan monolaurateipolyoxyethylene derivative (a commercial water-soluble :nonionic emulsifying agent) is then-mixed with the concen- To this mixture. andwith agitation is added suftrate. ficient water to, provide'an aqueous emulsion having a concentration of 0.1% by weight. of S-(1,1-dioxo-2,3--

phosphorodithioate.

dihydrothien-B-yl) 0,0-diethyl As illustrative of includes anyand all of those substancesqin which the phosphorothioates of .tliiS invention are ;dispersed. 'It includes, therefore, the; solvents of 5a truesolution, the liquid phase of suspensions, emulsions or aerosols, the

Thereupon Lima bean plant leaves. previously infested with .the two-spottedspider, mite, Terranychus telarius.

(L.),--.are dipped in the aqueous emulsion, withdrawn,

and set'aside'for observation, At the end of 48 hoursa a 100% killof themobile stage of the .mite' is noted.

Seven days after setting the .test specimen aside residual activity is confirmed, a 100% kill of both the resting stage and the, ova stage being noted. Similanresultsv against themobile, resting and ova stages ofthe same mite are obtained employing S-(1,1-dioxo-2,3rdihydrothien-3-yl) ,0,0-diisopropyl phosphorodithioate and S- (1,1-dioxo-2,3-dihydrothien-3-yl) '0,0-diethyl phospho-' rothioate respectively, at the same concentration.

' Residual activity is alsoobserved employing the com- I pounds of this invention against the adult red flour beetle, e.g. at a concentration of 1.0% by weight S-(1,l-dioxo.- 2,3-dihydrothien-3-yl) 0,0-diethy1 phosphorodithioate Employing S-(1,l-dioxo-Z,S-dihydrothien-S-yl) 0,0-di- I ethyl phosphorodithioate at a concentration of 0.08 ppm.

gave a 100% kill.

against yellow fever mosquito larvae, Aedes aegypti, 100% kill'is observed.

systemic-aotivity was also observed against a .Wide

variety of insects. For example against the two-spotted spider mite .Tetranychus telalrius (1...), a 100% killdsobserved employing S- 1,1-dioxoa2,3 dihydrothien-3-yl) QO-diethyl; phosphorodithioate at a. concentration of 0.01% by weight. Also for example against the Mexil-'dioxo-2,3-dlhydrothien-3-yl-)v 0,0-diethyl thioate at a concentration of 0.004%.

'50 can bean beetle a 100% kill is observed employing S-(1,-

phosphoro Although the phosphorothioates of. this invention 3' are useful per se in controlling a wire variety of insect pests, it ispreferable that they be supplied to the'pests:

or tothe environment of the pest or.pests in a dispersed.

form in a suitable extending agent.

'In the instant specification and .appended claims it .is to be understood-that the term dispersed isused in its 7 widest possible sense. When it is said that the phos phorothioates of this invention are dispersed, it;means that the particles of the phosphorothioates of this invention may be molecular in-size and held intrue solution in a suitable organic solvent.

out. a liquid phase in the form of suspensions or emulsions or in the form of particles held in suspensiomby wetting agents. It also includes particles which are distributed in a semi-solid viscous carrier such as petrolatuml or soap or other ointmentbase in which they may be actually dissolved in the semi-solid or held in suspension in the semi-solid with the-aid of suitable Wetting or emulsifying agents. The term dispersed also means that the 1 particles may be mixed withQand distributed throughout It means further, that. the; particles may becolloidal in :size and distributed through-r a solid carrier providing a persed also includes mixtures-which are suitable for use as aerosols including solutions, suspensions,or-emulsions of the phosphorothio'ates-of this invention in a carrier. such as dichloro-difluoromethane and like fluorochloroalkanes.

which boil below room temperature at atmospheric pressure.

In the instant'speoification andappended claims it is to be understood that the expression extending agent semi-solid carrier of ointments and the solid phase of par ticulate" solids, e.g. :pellets, granules, dusts: and powders.-

The exact concentration= of the phosphorothioates. of a this invention employed-in combatting or .controllingin sect pests can vary' considerably provided the required dosage (i.e.,- toxic or lethal, amount) thereof .is supplied to the pests or-to the environmentof the pests. When the: extending agent is a liquid ormixture ofliqjuids (eg'.

as in solutions, suspensions, emulsions,orraerosols) the concentration of the vphosphorothioate: employed to, sup:

ply. the desired dosage generally. will be in the range .of 1 0.001 to 50 percentby weight.) When the extending agent is a semi-solid .or solid, the concentration-of the. phos' phorothioate employed to supply the desired dosage generally will be-in the range .of 0.1 to 25 percent by weight. From a practical point of view, the manufacturer must supplythe agriculturist with ;a low-cost concentrate or spray base or particulate solid base \in such form that, by

merely mixing; with water or solidextender (e.g. powdered clay or talc) or other low-costmaten'al available to the agric'ulturist at-the pointof'use, he will have an easily prepared insecticidal spray or particulate solid. In such a concentrate composition, a the ,phosphorothioate generally willibe present in a concentrationof 5 to 95 percent by weight, the residue being any one or more of the well-known insecticidal adjuvants, such asthe various surface active agents -(e.g., detergents, a soap or other emulsifying or wettingagent; surface-active :clays), sol-. vents, diluents, carrier media, adhesives, spreading. agents, humectants,and the like.

There are a large number of organic liquidswhich can i erably above tabout.90 percent. In thoseinstances wherein there may be concern aboutithe phytoxicity of the organic liquid extendingagent a portion of samecan be replaced by such low molecular zweightraliphatic. hydrocarbons as dipentene,diisobutylene,propylene trimer, and

the like or'suita'ble; polar organic liquids such as the .a li-. phatic .ethers: and :the aliphatic ketones containing not more than about 10 carbonatoms .as exemplifiedby acetone, methyl ethyl ketone, diisobutylketone, dioxane,

isopropyl; ether;'and.the like. In certain instances, it is; advantageous to. employ a mixture of organic liquids as the extending agent.

When the 'phosphorothioates of this invention are .to be supplied tothe insect. pests or to the environment of.

the pests as aerosols, it is convenient'to dissolve them in a suitable solvent and disperse the resulting solution in, dichlorodifluromethane or like vchlorofluoroalkane which boils below room temperature at atmospheric pressure,

mixture in. particulate form, eg pellets, granules powders, or dusts;. The term dis- The phosphorothioates of this invention are' preferab'ly supplied to the insect pests or to the environment of the insect pests in the form of emulsions or suspensions. Emulsions or suspensions are prepared by dispersing the phosphorothioates of this invention either per se or in the form of an organic solution thereof in water with the aid of a water-soluble surfactant. The term surfactant as employed here and in the appended claims is used as in volume II of Schwartz, Perry and Berchs Surface Active Agents and Detergents (1958, Interscience Publishers, Inc., New York), in place of the expression emulsifying agent to connote generically the various emulsifying agents, dispersing agents, wetting agents and spreading agents that are adapted to be admixed with the active compounds of this invention in order to secure better wetting and spreading of the'active ingredients in the water vehicle or carrier in which they are insoluble through lowering the surface tension of the water (see also Frear, Chemistry of Insecticides, Fungicides and Herbicides, second edition, page 280). These surfactants include the well-known capillary-active substances which may be anion-active (or anionic), cation-active (or cationic), or non-ionizing (or non-ionic) which are described in detail in volumes I and II of Schwartz, Perry and Berchs Surface Active Agents and Detergents (1958 Interscience Publishers, Inc., New York), and also in the November 1947 issue of Chemical Industries (pages 811-824) in an article entitled Synthetic Detergents by John W. McCutchcon and also in the July, August, September and October 1952 issues of Soap and Sanitary Chemicals .under the title Synthetic Detergents. The disclosures of these articles with respect to surfactants, i.e. the anion-active, cation-active and non-ionizing capillary active substances, are incorporated in this specification by reference in order to avoid unnecessary enlargemerit of this specification. The preferred surfactants are the water-soluble anionic surface-active agents and the water soluble non-ionic surface-active agents set forth in U.S. 2,846,398 (issued August 5, 1958). In general it is preferred that a mixture of water-soluble anionic and water-soluble non-ionic surfactants be employed.

The phosphorothioates of this invention can be dispersed by suitable methods (e.g.,tumbling or grinding) in solid extending agents either of organic or inorganic nature and supplied to the insect pest environment in particulate form. Such solid materials include for example, tricalcium phosphate, calcium carbonate, kaolin, bole, kieselguhr, talc, bentonite, fullers earth, pyrophyllite, diatomaceou-s earth, calcined magnesia, volcanic ash, sulfur and the like inorganic solid materials, and include for example, such materials of organic nature as powdered cork, powdered wood, and powdered walnut shells. The preferred solid carriers are the adsorbent clays, e.g. bentonite. These mixtures can be used for insecticidal purposes in the dry form, or, by addition of water-soluble surfactants or wetting agents; the dry particulate solids canbe rendered wettable by water so as to obtain stable aqueous dispersions or suspensions suitable for use as sprays.

For special purposes the phosphorothioates of this invention can be dispersed in a semi-solid extending agent such as petrolaturn or soap (e.g. sodium stearate or oleate or palmitate or mixtures thereof) with or without the aid of solubility promotors and/ or surfactants or dispersing agents.

In all of the forms described above the dispersions can be provided ready for use in combatting insect pests or they can be provided in a concentrated form suitable for mixing'with or dispersing in other extending agents. As illustrative of a particularly useful concentrate is an intimate mixture of phosphorothioates of this invention with a water-soluble surfactant which lowers the surfaee tension of water in the weight proportions of 0,1 to 15 parts of surfactant with sufficient of the phosphorothioate of this invention to make 100 parts by weight. Such a is also water-soluble.

concentrate is particularly adapted to be made into a spray for combatting various forms of insect pests (particularly mites) by the addition of water thereto. As illustrative of such a concentrate is an intimate mixture of 95 parts by weight of S-(1,1-dioxo-2,3-dihydrothien-3- yl) 0,0-diethyl phosphorodithioate and 5 parts by weight of a water-soluble non-ionic surfactant such as the polyoxyethylene derivative of sorbitan monolaurate.

Another useful concentrate adapted to be made into a spray for combatting insect pests (particularly mites) is a solution (preferably as concentrated as possible) of a phosphorothioate of this invention is an organic solvent therefor. The said liquid concentrate preferably contains dissolved therein a minor amount (e.g., 0.5 to 10 percent by weight of the weight of the new insecticidal agent) of a surfactant (or emulsifying agent), which surfactant As illustrative of such a concentrate is a solution of S-(1,1-dioxo-2,3-dihydrothien-3-yl) 0,0-diethyl phosphorothioate in benzene which solution contains dissolved therein a water-soluble polyoxyethylene glycol non-ionic surfactant and a water-soluble alkylaryl sulfonate anionic surfactant.

Of the surfactants aforementioned in preparing the various emulsifiable, wettable or dispersible compositions or concentrates of this invention, the anionic and nonionic'surfactants are preferred. Of the anionic surfac- 'tants, the particularly preferred are the well-known water'- soluble alkali metal alkylaryl sulfonates as exemplified by sodium decylberizcne sufonate and sodium dodecylbenzene sulfonate. Of the non-ionic surfactants, the

particularly preferred are the water-soluble polyoxyethylene derivatives of alkylphenols (particularly isooctylphenol) and the water-soluble polyoxyethylene derivatives of the mono-higher fatty acid esters of hexitol anhydrides such as mannitan or sorbitan.

In all of the various dispersions described hereinbefore for insecticidal purposes, the active ingredients can be one or more of the compounds of this invention. The compounds of this invention can also be advantageously employed in combination with other pesticides, including, for example, nematocides, bacterocides, and herbicides. In this manner, it is possible to obtain mixtures which are effective against a wide Variety of pests and other forms of noxious life.

In controlling or combatting insect pests the phosphorothioates of this invention either per se or compositions comprising same are supplied to the insect pests or to their environment in a lethal or toxic amount. This can be done by dispersing the new insecticidal agent or insecticidal composition comprising same in, on or over an infested environment or in, on or over an environment the insect pests frequent, e.g. agricultural soil or other growth media or other media infested with the insect pests or att'ractable to the pests for habitational or sustenance or propagational purposes, in any conventional fashion which permits contact between the insect pests and the phosphorothioates of this invention. Such dispersing can be brought about by applying the phosphorothioates per se or sprays or particulate solid compositions containing same to a surface-infested with the insect pests or attractable to the pests, as for example, the surface of agricul tural soil or other media such as the above ground surface of plants by any of the conventional methods, e.g.

power dusters, broom and hand Sprayers, and spray dusters. Also for sub-surface application such dispersing can be carried out by simply mixing the new insecticidal agent per se or insecticidal spray or particulate solid compositions comprising samewith'the infested environment or with the environment the insect pests frequent, or by employing a liquid carrier for the new insecticidal agent to accomplish sub-surface penetration and impregnation therein.

While this invention has been described with respect to certain embodiments, it is to be understood that it is not so limited and that variations and modifications there- 7 of obvious to those skilled in the art can he made Without departing from the spirit and scope thereof.

What is claimed is: 1. The method for protection of plants against insect attack which comprises applying to the plant an insectit cidal amount of at least :one phosphorothioate of thewherein'X is selected from the group C nsisting Oil Sulfur and oxygen and wherein R" and R arealkyl. having i 1 to carbon atoms.

2. An insecticidal composition comprising a 'PlliDSPhOI'O- t thioate ofthe formula CH-OHS-P v v (in Hz OR s 02 wherein X is selected from the group consistmg of sulfur and oxygen, and wherein R" and R' are alkyl having 1 to 5 carbon atoms dispersed in an extendingagent selected from the .class consisting of solid and semi-solid extending agents, the composition containingfll to 25 T ing 1 to 5 carbon atoms dispersed in a liquid extending agent, the composition containing 0.001 to 50 percent by weight of said phosphorothioate.

4. .An insecticidal composition comprising a phosphorodithioate of the formula whereinR and R are alkyl having not more than:two 1 carbon atoms dispersed in an adsorbent clay, the composition c-ontaining 0.1 to 25 per-cent by weight of said phosphorodithioate.

5. An insecticidal concentrate comprising a phosphorodithioate of the formula wherein R and R are alkyl having not more than two 7 carbon atoms and an insecticidal adjuvant, said concentrate containing from 5 to 95 percent by weight of said phosphorodithioate.

6.:An insecticidal concentrate comprising a phosphorodithioate of the formula wherein R and R' are alkylhaving not morethanatwo carbon atoms: dispersed in an organic solvent therefor and having dissolved therein a minor amount of asurfactant, said concentrate? forming an emulsion with water 1 upon agitation therewith.

7. Antinsecticidal concentrate adapted tobe made into :a sprayable composition by the addition of water corn-y prising ;a phosphorodithioate of t the formula lie wherein R and R5 are alkyl having not -more1than.two carbon atoms in admixture with a water-soluble surfactant in the weight proportion of 0.1 to 15 parts of surfactant and sutficlent of said phosphorodithioateto make parts by weight. 7

8.-The method-of controlling insects which comprises contacting the insects with a toxic amount of a phoS-: phorothioate of the formula e fJH o1Is1I CH H,

wherein X is selected from the group consisting of sulfur and oxygenandwherein Rf. andR'" are alkylhay-ving 1 to 5 carbon atoms.: 9. The method of controlling insectswhichcomprise contacting the insects with a toxic amount of a phoswherein Re -and R- areHalkyl-havingnot more than two carbon atoms.

10. The method foriprotection of plants; against insect attack which comprises applyingto the plant an insecti' cidal amountiof at least one phosphorod-ithioate:ofthe 50 forrnula wherein R and t R are alkyl having not more than two,

carbon atoms.

11:2The method of controllinginsectswhich comprises contacting-the insects with a toxic amount of S-(-1,1- dioxo-Z,B-dihydrothiemB-yl) 0,0-diethy1 thioate.

12.1Theflmethod for protection of plants against insect attack whichgcomprises applying to the plant an insecticidal amount of S-(1,1-dioxo-2,3:dihydrothien-S-yl)i 0,0- diethyl phosphorodithioatei References Cited by the Examine:

UNITED STATES PATENTS 2,882,278

JULIAN S. LEVITT,Primary Examiner.

phosphorodi- 1 4/1959 McConnell et al. 167-'-33' V 

8. THE METHOD OF CONTROLLING INSECTS WHICH COMPRISES CONTACTING THE INSECTS WITH A TOXIC AMOUNT OF A PHOSPHOROTHIOATE OF THE FORMULA 